ebpf_exporter

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package decoder
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import (
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	"bytes"
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	"os"
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	"testing"
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	"github.com/cloudflare/ebpf_exporter/v2/config"
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	"github.com/cloudflare/ebpf_exporter/v2/kallsyms"
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)
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func TestKStackDecoder(t *testing.T) {
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	cases := []struct {
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		in  []byte
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		out []byte
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	}{
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		{
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			in: []byte{
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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			},
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			out: []byte(""),
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		},
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		{
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			in: []byte{
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				0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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			},
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			out: []byte("one\none\ntwo"),
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		},
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		{
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			in: []byte{
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				0xab, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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			},
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			out: []byte("three\ntwo\ntwo"),
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		},
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		{
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			in: []byte{
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				0xab, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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			},
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			out: []byte("three\nzero"),
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		},
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		{
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			in: []byte{
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				0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0xac, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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			},
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			out: []byte("??\nthree\n??"),
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		},
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	}
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	fd, err := os.CreateTemp("", "kallsyms")
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	if err != nil {
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		t.Fatalf("Error creating temporary file for kallsyms: %v", err)
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	}
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	defer os.Remove(fd.Name())
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	_, err = fd.WriteString("0000000000000004 T one\n0000000000000006 T two\n00000000000000aa T three\n")
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	if err != nil {
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		t.Fatalf("Error writing fake kallsyms data to %q: %v", fd.Name(), err)
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	}
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	decoder, err := kallsyms.NewDecoder(fd.Name())
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	if err != nil {
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		t.Fatalf("Error creating ksym decoder for %q: %v", fd.Name(), err)
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	}
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	_, err = fd.WriteString("0000000000000002 T zero\n")
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	if err != nil {
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		t.Fatalf("Error writing additional fake kallsyms data to %q: %v", fd.Name(), err)
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	}
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	d := KStack{decoder}
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	for _, c := range cases {
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		out, err := d.Decode(c.in, config.Decoder{})
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		if err != nil {
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			t.Errorf("Error decoding %#v: %s", c.in, err)
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		}
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		if !bytes.Equal(out, c.out) {
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			t.Errorf("Expected %q, got %q", c.out, out)
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		}
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	}
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}
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